The scars of the dot-com crash over a decade ago are still visible in London’s financial district and it goes some way to explain why tech start-ups and bankers haven’t been doing lots of business, even when the return on investment is potentially so high.

To understand why, we talked to London’s tech start-ups and entrepreneurs to find out what they think about banks and equity markets.

Earlier this month, Noam Bardin, a tech entrepreneur and chief executive of Waze, a start-up that builds traffic apps for communities, said in a blog post: “Why not stay completely independent? We asked ourselves: ‘Will Waze still be a fun project to participate in, and a fun place to work, as a stand-alone public company?’ Choosing the path of an IPO often shifts attention to bankers, lawyers and the happiness of Wall Street, and we decided we’d rather spend our time with you, the Waze community.”

The tart statement encapsulates two key challenges to London as a market for initial public offerings: first, some skepticism within the tech community over the appeal of the equity markets, and second, the entrenched position of Wall Street, rather than the U.K.’s Square Mile, as the destination for technology flotations.

The London Stock Exchange is launching a new niche market targeting high-growth companies and allowing them to float.

The High Growth Segment will be open to companies that are incorporated in the European Economic Area, that have a historic compound annual growth rate of 20% over three years and have a market capitalization of at least £300 million ($467 million). Those that comply will have the minimum free float lowered from 25% to 10%.

There have been no tech IPOs in London since the Russian giant Mail.ru, and that was almost two years ago, in November 2010, raising $912 million.

MOSCOW–Rovio Entertainment Ltd., the Finnish firm behind the wildly successful mobile app “Angry Birds,” has no plans for an initial public offering anytime soon as the firm is already “insanely profitable” and can afford to finance its own growth, the company’s chief marketing officer said Monday.

“For us right now, we are running a very successful operation, we are growing very, very fast and we are insanely profitable so we can fund can fund our own growth,” Peter Vesterbacka said in Moscow at an event announcing the launch of “Angry Birds” soda in Russia.

The comment shooting down listing plans comes after years of repeated suggestions from company officials that the small firm was readying to go public. Last May, when the company announced its 2011 earnings, officials said it was preparing itself for an eventual listing. In 2011, Mr. Vesterbacka said the company was planning to list as much as $1 billion worth of shares in 2012. In August, 2012, Rovio’s chief financial officer said the company might list by the end of 2013.

The U.K. government is looking to make it easier for high-growth companies to launch initial public offerings in London as part of its strategy to make London Europe’s high-tech capital, the government announced Thursday.

However investors, while welcoming the move, said it would not necessarily persuade them to recommend companies to float in London.

Proposals include a planned new route to the U.K. IPO market for high-growth companies, which is likely to feature reformed rules on free float, eligibility criteria and reporting requirements. Acting as a “launch pad” for companies seeking a full premium listing, the move was aimed in particular at mid-sized, high-growth businesses in Europe that are currently underrepresented on U.K. exchanges.

About Tech Europe

Tech Europe covers Europe’s technology leaders, their companies, and the people and industries that support them — and their ideas. The blog is edited by Ben Rooney, with contributions from The Wall Street Journal and Dow Jones Newswires.